powerpc/perf/imc: Use cpu_to_node() not topology_physical_package_id()

init_imc_pmu() uses topology_physical_package_id() to detect the
node id of the processor it is on to get local memory, but that's
wrong, and can lead to crashes. Fix it to use cpu_to_node().

Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support")
Cc: stable@vger.kernel.org # v4.14+
Reported-By: Rob Lippert <rlippert@google.com>
Tested-By: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/perf/imc-pmu.c

@@ -467,7 +467,7 @@ static int nest_imc_event_init(struct perf_event *event)
 	 * Nest HW counter memory resides in a per-chip reserve-memory (HOMER).
 	 * Get the base memory addresss for this cpu.
 	 */
-	chip_id = topology_physical_package_id(event->cpu);
+	chip_id = cpu_to_chip_id(event->cpu);
 	pcni = pmu->mem_info;
 	do {
 		if (pcni->id == chip_id) {
@@ -524,19 +524,19 @@ static int nest_imc_event_init(struct perf_event *event)
  */
 static int core_imc_mem_init(int cpu, int size)
 {
-	int phys_id, rc = 0, core_id = (cpu / threads_per_core);
+	int nid, rc = 0, core_id = (cpu / threads_per_core);
 	struct imc_mem_info *mem_info;
 
 	/*
 	 * alloc_pages_node() will allocate memory for core in the
 	 * local node only.
 	 */
-	phys_id = topology_physical_package_id(cpu);
+	nid = cpu_to_node(cpu);
 	mem_info = &core_imc_pmu->mem_info[core_id];
 	mem_info->id = core_id;
 
 	/* We need only vbase for core counters */
-	mem_info->vbase = page_address(alloc_pages_node(phys_id,
+	mem_info->vbase = page_address(alloc_pages_node(nid,
 					  GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE |
 					  __GFP_NOWARN, get_order(size)));
 	if (!mem_info->vbase)
@@ -797,14 +797,14 @@ static int core_imc_event_init(struct perf_event *event)
 static int thread_imc_mem_alloc(int cpu_id, int size)
 {
 	u64 ldbar_value, *local_mem = per_cpu(thread_imc_mem, cpu_id);
-	int phys_id = topology_physical_package_id(cpu_id);
+	int nid = cpu_to_node(cpu_id);
 
 	if (!local_mem) {
 		/*
 		 * This case could happen only once at start, since we dont
 		 * free the memory in cpu offline path.
 		 */
-		local_mem = page_address(alloc_pages_node(phys_id,
+		local_mem = page_address(alloc_pages_node(nid,
 				  GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE |
 				  __GFP_NOWARN, get_order(size)));
 		if (!local_mem)